The impact of network noise at large-scale communication performance

The impact of operating system noise on the performance of large-scale applications is a growing concern and ameliorating the effects of OS noise is a subject of active research. A related problem is that of network noise, which arises from shared use of an interconnection network by parallel processes. To characterize the impact of network noise on parallel applications we conducted a series of simulations and experiments using a newly-developed benchmark. Experiment results show a decrease in the communication performance of a parallel reduction operation by a factor of two on 246 nodes. In addition, simulations show that influence of network noise grows with the system size. Although network noise is not as well-studied as OS noise, our results clearly show that it is an important factor that must be considered when running large-scale applications.